hrpM IS INVOLVED IN GLUCAN SYNTHESIS, BIOFILM FORMATION AND PATHOGENICITY OF Xac

VALERIA CONFORTE; FLORENCIA MALAMUD; RAFAEL HOMEN; MARÍA ROSA MARANO; ATILIO CASTAGNARO; ALEXANDRE DO AMARAL; ADRIÁN VOJNOV

Puerto Madryn

Congreso; 46th Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2010

SAIB

One of the most devastating citrus diseases is bacterial citruscanker caused by Xanthomonas axonopodis pv. citri (Xac).Previous work from our laboratory demonstrated that Xac is able toform biofilm communities in biotic and abiotic surfaces. To obtainnew genes involved in Xac biofilm formation we performed ascreening using a library of 6000 tn5 mutants. Mutants with lessadherence than the wild type strain to polystyrene surface after 24hours of growth in Y-minimal medium were chosen. One of themutant obtained from the screening corresponded to an insertion inhrpM gene, encoding a glucosyltransferase enzyme. According tohrpM gene homology with identified sequences in other bacteria, itis a candidate for the cyclic â-1, 2-glucan synthesis in Xac. Here wedemostrated that the disruption of this gene compromised theproduction of the cyclic â-(1,2)-glucan. Moreover, this mutantshowed reduced swimming motility and biofilm development.Bacterial suspensions were inoculated in lemon and grapefruitplants and no disease symptoms were observed in leaves infectedwith the hrpM strain.